Re: [Mesa3d-dev] Bug in z-depth

[Brian P. <br...@va...>]

Klaus Niederkrueger wrote:
> 
> Hi,
> 
> There seems to be a bug in the depth-buffer code. That looks very strong like an rounding-error or something. On
> http://www.math.leidenuniv.nl/~klaus/bug.jpg
> you can see a screenshot I made. With Mesa-3.2 it looks o.k.
> 
> The error was produced by using Crystal-space. I believe it works like this (but I'm not sure): The walls are drawn with activated z-Buffer (but without z-Buffer testing) and afterwards objects are drawn with z-Buffer-test activated.

I'm assuming that you're using software rendering (Xlib driver).

When I've seen this sort of thing before it usually caused by using "bad"
near/far clip plane positions.  What are your arguments to glFrustum?
If the ratio of far:near is greater than 1000 you should adjust the
values.

Also, you could check the depth of your Z buffer with
glGetIntegerv(GL_DEPTH_BITS, &bits).  I'd expect it to be 16 bits, but
maybe it's not.

-Brian